1. Field of the Invention
The invention relates to an X-ray apparatus which includes an X-ray source for emitting X-rays, an examination space for receiving an object to be radiologically examined, an X-ray detector for deriving an image signal from an X-ray image of the object, and an X-ray filter for locally attenuating the X-rays, which X-ray filter is arranged between the X-ray source and the X-ray detector, and is provided with filter elements whose X-ray absorptivity can be adjusted on the basis of a quantity of X-ray absorbing liquid within the individual filter elements.
2. Description of Related Art
An X-ray examination apparatus of this kind is known from international patent application WO 96/13040.
The known X-ray examination apparatus includes an X-ray filter whose filter elements are constructed as capillary tubes. One end of the capillary tubes communicates with a reservoir containing an X-ray absorbing liquid. The quantity of X-ray absorbing liquid within the individual capillary tubes is controlled on the basis of an electric adjusting voltage applied to the individual capillary tubes. Capillary tubes filled with an X-ray absorbing liquid partly attenuate X-rays passing through the relevant tubes. In the known X-ray examination apparatus it is not easily possible to shield the object to be radiologically examined, for example a patient to be examined, properly from the X-rays in areas of the patient that need not be exposed. In the known X-ray examination apparatus it is notably not very well possible to form an X-ray beam which is limited so as to expose only a predetermined part of the patient. The part to be exposed is chosen, for example on the basis of the suspected disorder of the patient to be examined.